FT. BRAGG, N.C. -- Sobbing and burying her head in her hands, a U.S. Army captain testified Friday that Brig. Gen. Jeffrey Sinclair twice forced her to perform oral sex in her office in Afghanistan after she demanded that he remove her from her job working directly for him.

The sexual assaults took place with her office door open in a military office complex on busy Kandahar Air Field, she testified. In the first attack, she said, Sinclair roughly pushed her head and shoulders down after she told him, "I hated my life. I hated working for him."

The captain said she tried to resist the assaults inside her tiny office, but Sinclair was too strong. The second assault took place a week later, she said.

Choking back tears on the witness stand, she said she pushed him away and told him during the second assault: "If you ... touch me again I’ll scream and I don’t care who hears."

The allegations by the captain, 34, came on the first day of testimony by a prosecution witness in the court-martial of Sinclair, 51, who was deputy commander for U.S. troops in southern Afghanistan. She said the assaults took place around December 2011, after an off-and-on extramarital affair that lasted nearly three years across three continents.

Early in their relationship, while both were serving in Iraq, Sinclair threatened to kill the captain and her family if she divulged the affair, she testified. She said he told her that he would "do it in a way no one would ever know." He added, according to the captain: "You need to know what you’re dealing with."

She also testified that Sinclair fondled her breasts and crotch against her will on a military flight from Baghdad to Kuwait, on a plane that was jammed with soldiers.

Sinclair, one of the few generals to face a court-martial in the last half-century, is charged with sexual assault, sodomy, groping and fondling the captain, having sex in public and abusing his government credit card in pursuit of trysts with the captain. He faces life in prison if convicted on all charges.

On Thursday, Sinclair pleaded guilty to adultery, improper relationships with three other women, impeding an investigation and viewing pornography in a war zone. He will be sentenced by the jury at the conclusion of the court-martial.

The accuser, often weeping and wiping her eyes with a tissue, testified for nearly five hours about the tumultuous sexual relationship she says she had with the married general. They had sex in a parked car in Germany, on a hotel balcony in Arizona and in their base offices in the southern Afghan desert, she told a jury panel of five male two-star generals.

She tried several times to break things off, she testified, but she was in love with Sinclair and even pursued him at one point after he stopped taking her phone calls. She felt so ashamed and unworthy that she once told Sinclair she was contemplating suicide, she testified.

"I didn’t know how I could tell him I didn’t want to be with him anymore," she said. "I was scared to death of how that would go."

She wanted more from a relationship, she said. "I didn’t want to be a woman on the side, just being used for sex."

The captain testified under a grant of immunity. Adultery is a serious offense in the military.

Earlier in the day, lead prosecutor Lt. Col. Robert Stelle told jurors: "This is a case where nonconsensual sex was used as an instrument of control." He accused Sinclair of "abuse of position, abuse of command authority, abuse of power, abuse of rank.’’

Stelle said the general ignored a direct order from his superior not to contact the accuser, issued the same day in March 2012 that she made the sexual assault allegations. Sinclair tried three time that day to telephone the captain, Stelle said, but his calls went unanswered because the phone was by then in the custody of military investigators.

The general could be rough and demanding, the captain said. After they had sex in a hotel in Tucson, she said, Sinclair slammed her against a door and choked her when she tried to leave.

On another occasion, she said, the general forbade her to have sex with her boyfriend, telling her: "You belong to me."

In Iraq, she said, he forced her to urinate in a trash can in his quarters to avoid being seen by going outside to a toilet.

The captain struggled to explain why she told no one of the death threats for two years and continued to have sex with Sinclair -- or why she did not immediately report the alleged sexual assaults.

She testified that she had once willingly performed oral sex on the general in her office before the alleged assaults. While receiving oral sex, Sinclair paused three or four times to lean into the hallway and speak to other officers in the complex, she said.

Under gentle questioning from Stelle, the captain said Sinclair was regarded as "a god" in the 82ndAirborne Division. She said she feared "the 82ndwould try to cover it up and make it look like I was crazy" if she complained about what was happening.’

"I felt like there was no hope, sir," she told Stelle. "You don’t make accusations against people in the 82nd.... It was going to be my word against his, and nobody would believe me. I had no way out."

In addition, she said, she feared that Sinclair would find a way to fire her and ruin her career.

"Who was going to believe my word against a one-star general?" she said.

She said she learned during the relationship not to anger Sinclair. He sexually assaulted her moments after she demanded he transfer her away because, she said, "I couldn’t stand being on the same base as him."

She said she never had sex with him again after the assaults.

"It felt disgusting," she said of the assaults. "It felt like I had no control over my body."

The captain, who is fluent in Arabic, served as Sinclair’s advisor in meetings with Afghan tribal leaders, although she did not speak the local languages, Dari or Pashto. While serving in the same position under Sinclair in Iraq, the defense said, the accuser fought hard to get her job back after she was briefly replaced by a male officer.

In opening statements earlier Friday, the government portrayed Sinclair as a scheming sexual predator who pursued impressionable junior officers, especially the captain.

The defense described the captain as a woman who told Sinclair in emails how much she enjoyed sex with him, and continued to exchange texts and emails even after he allegedly groped her, threatened her life and sexually assaulted her.

Defense lawyer Ellen C. Brotman told jurors that the accuser sent emails to the general on the very day in March 2012 that she finally decided to tell Sinclair’s superior officer that they'd had an affair and Sinclair had assaulted her.

Brotman said the captain’s version of events is undermined by her own journal entries, and by reams of texts and email exchanges with Sinclair.

The captain "never did anything she didn’t want to during the three years the relationship lasted," Brotman said. "Her own words will speak this truth."

Referring to the captain’s journal entries, Brotman told jurors: "What you will not hear is one iota of a fear for her career, her safety or her family’s safety." Instead, she said, the accuser feared the general would not divorce his wife after promising her that he would.

Brotman read aloud from the captain’s journal: "My biggest fear is that there is still something there in his marriage."

The defense contends that the captain made the sexual assault allegations to retaliate against Sinclair for pursuing another woman. Just hours before she revealed the affair, Brotman said, the captain discovered chatty "I love u" emails between Sinclair and another female captain while reviewing Sinclair’s emails as part of her job in Kandahar.

That caused the captain to "explode into fury," Brotman said. Using the general’s email account, the accuser fired off three angry emails to the other captain, whom she did not know. In one email, she told the woman that she wasn’t the only one having sex with the general.

"Her dreams are crashing down around her, and she can’t keep it inside any more," Brotman said.

Even so, Brotman said, the accuser emailed Sinclair the same day to thank him for picking up a gun holster while on leave in the U.S.: "Thank you, sir. You are GREATLY missed here."

Two days earlier, she emailed the general: "I owe you." The word "owe" was code between the two for "love," according to Brotman.

Earlier in their relationship, Brotman said, the accuser referred to sex with Sinclair as "deployment sex," implying that it would end when the deployment was over.

And, according to Brotman, the accuser threatened to commit suicide only "as a ruse to get Brig. Gen. Sinclair’s attention."

"False suicide claims, false sexual assault claims," Brotman said.

Testimony continues Monday with cross-examination of the captain. Sinclair's lead attorney said he looked forward to it.